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neothehacker avatar image
neothehacker asked

Phoenix Smart IP43 voltage too high for my AGM?

Community,


I have my Phoenix Smart IP43 charger setup to load my Varta Professional AGM 95ah battery.

I set the setting to AGM spiral cell, the values match w/my battery. A shame that there is no general AGM setting :(

I also have a smart sense temperature sensor linked in the smart network.

What I noticed though was that the charger at some point had 14.9-15.0 V. That is too high for the battery? I wonder because the setting AGM Spiral says 14.8 max.

Any ideas?

AGM BatteryPhoenix Smart Charger ip43
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1 Answer
Stefanie (Victron Energy Staff) avatar image
Stefanie (Victron Energy Staff) answered ·

@neothehacker

AGM spiral cell is not the profile of choice for your AGM. I suggest using one of the gel battery profiles or, even easier, create a preset specifically for your battery. I also have a Varta 95Ah AGM which is very happy with an absorption voltage of 14.40V and a float voltage of 13.80V.

The high voltage you are seeing is most likely the result of temperature compensation. You can see the setting for this if you turn on the "Expert" settings.

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neothehacker avatar image neothehacker commented ·

Hi Stefanie, thanks for your reply!

Yeah, I will create a new profile as suggested.

Interesting w/the temp compensation. Does that mean it would increase voltage when the battery is cold? Battery was at 9 C Celsius.

My understanding was that temp compensation only lowers voltage in very warm conditions.

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Stefanie (Victron Energy Staff) avatar image Stefanie (Victron Energy Staff) ♦♦ neothehacker commented ·

No. Temperature compensation (if enabled) kicks in for each degree Celsius below or above 25°C. 25°C is the base. If temperature compensation is active for your battery profile, then this makes 16°C (25°C - 9°C) x 16.20mV (default value) = ~0.265V, which is what you're seeing.

It is recommended to enable temperature compensation for temperatures below 10°C or above 30°C and disable it for temperatures in the normal range. Best is to follow the battery manufacturer's instructions, also for the correct value of temperature compensation.

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